Protein substrates for proteinases with double fluorescent fluorophors are synthesized. Pyridoxal-5'-phosphate, dansyl chloride and fluorescein isothiocyanate were used as fluorescent sounds for modification of globin. Phosphoyridoxyl fluorophor was present in the both substrates. The second label was either fluoresceinthiocarbamyl or dansyl fluorophor. Spectral characteristics and ability to hydrolysis of obtained substrates have been studied. The influence of some salts on fluorescent characteristics of those substrates have been analyzed. Differentiation of the hydrolyzed substrate from the initial one by ammonium sulphate is shown to be possible.